Motion/occupancy sensors are known to provide an economical solution for controlling energy delivery to various electrical systems, such as lighting systems in a residence, commercial building, outdoor area, or any other place where it is desired to limit energy delivery to those times when the controlled space is occupied. One of the primary benefits of utilizing occupancy sensors for this purpose is substantial energy savings which results in corresponding cost savings, not to mention conserving valuable natural resources. Occupancy sensors are often considered to be most suitable when the area to be controlled is intermittently occupied, for example, when a room is unoccupied for two or more hours per day, and where one or more lights in the area is regularly left ON when the space is unoccupied. This type of situation makes occupancy-based lighting control a very desirable solution for areas such as parking garages and exterior lighting applications. Studies have shown that Motion/Occupancy detection systems used to control parking garages and exterior lighting can provide energy savings of up to 30% to 60%, and possibly more.
In addition to providing a cost-effective method for reducing energy consumption, additional uses for occupancy sensors include security (e.g., by indicating that a particular area is occupied, or not), and reducing light pollution (e.g., by limiting the amount of lighting operated at night). Historically, due to reasons that include relatively low energy costs, security concerns, and the lack of a truly robust low-cost occupancy detection technology, the market has been reluctant to deploy occupancy detection for parking garage and outdoor lighting applications. This reluctance is waning, however. Recent code changes, such as to the California Energy Code (CEC), Title 24, and the addition of new wide-reaching energy-related standards, such as ASHRAE/IES 90.1, have led to strengthened language in Codes of many jurisdictions and led to the addition of more energy-delivery control requirements that now include parking garages and exterior lighting. These changes include, for example, adding a requirement for occupancy detection as a means of reducing lighting levels when these lighting zones are unoccupied. The development of a new robust luminance and motion/occupancy sensor capability for lighting applications provides a solution that addresses these new code and standard requirements, as well as additional concerns.